1. Field of the Invention
The present invention relates to an ophthalmic apparatus for measuring and observing an eye and, more particularly, to an ophthalmic apparatus provided with a system to indicate alignment information and others to an operator.
2. Description of Related Art
Ophthalmic apparatuses for measuring and observing generally have optical systems for observing an examinee's eye, because those apparatuses require the accurate alignment between the apparatus and the examinee's eye. For the observing optical system, there are some kinds of an optical system for photographing the examinee's eye with a CCD camera and the like and then projecting the image of the eye on a TV monitor, and another optical system for directly observing the examinee's eye through an observing lens.
The former system commonly displays the alignment information and examined data with the image of the eye in the same field of view on a TV monitor, by introducing displaying luminous flux to the observing optical system or by utilizing a character displaying circuit and a graphic displaying circuit and the like.
The latter direct observing system utilizes introducing luminous flux for displaying the information into an observing optical system and, alternatively, displaying the information at out of observation visual field of an examiner so that the examiner observes the examinee's eye and a display portion alternately.
However, the former system should be provided with CCD cameras and TV monitors and others and therefore causes the increased cost of apparatus and large-sized apparatus. The system is not suitable at all for hand-held type apparatus consequently.
An apparatus with the latter system, wherein a display unit is disposed at out of the observation visual field of the examiner, has a troublesome problem that the the examiner must turn his eye on the examinee's eye and the display alternately. The system for introducing the luminous flux from the display unit into the observation visual field must provide the optical path for the displaying luminous flux and dispose a light synthesizing member. Accordingly, the apparatus with the system, increasing in size, is not always suitable for hand-held type apparatus.